By Mick O’Neill, M.Sc., P.Geo.,Industry Liaison Geologist
The Province of Nova Scotia has a key role to play in Canada’s critical mineral supply chain, through exploration, mining, processing, manufacturing, and recycling, and in support of the province as it moves toward a low-carbon economy and a goal of net-zero greenhouse gas emissions by 2050. Nova Scotia, though small in comparison to other provinces and territories, has a diverse geologic history, representing most of the Phanerozoic Eon.
Nova Scotia is a past producer of many critical minerals including copper, zinc, antimony, tin, and tungsten demonstrating the opportunity to discover and develop many other critical mineral deposits across the province.
In addition to its rich geology and mining history, the province has available many excellent online resources for companies and prospectors to plan exploration work in Nova Scotia, including NovaScan, the Nova Scotia Geoscience Maps and Publications Database, and NOVAROC, a web-based application for the acquisition and maintenance of mineral claims in the province. Other information can be found at the Geoscience and Mines Branch website, including the Mineral Occurrence Database, the Abandoned Mine Openings Database, Geoscience Atlas, and the Drillhole Database.
Nova Scotia’s Department of Natural Resources and Renewables has developed a list of 16 critical minerals, outlined in Nova Scotia’s Critical Minerals Strategy. Using the four criteria identified in the strategy, minerals containing the following elements have been deemed critical: antimony, cobalt, copper, graphite, germanium, gallium, indium, lithium, manganese, molybdenum, niobium, rare earth elements (REE), tantalum, tin, tungsten, and zinc. A summary of critical mineral prospects and occurrences is shown in Figure 1, highlighting the potential for Nova Scotia to contribute critical minerals to the global supply chain. The list is under review and an updated list will be published later this year.
Some key areas of Nova Scotia’s critical mineral potential are highlighted in the recent article, Developing Canada’s critical mineral supply chain in Nova Scotia, with details on five properties: Brazil Lake Lithium Project, Coxheath Copper-Molybdenum porphyry-epithermal system, Scotia Mine Zinc-Lead Mississippi Valley-type deposit, East Kemptville Tin-Indium past-producing mine, and the Frenchvale flake graphite property (2023 NI 43-101 report).
Antimony
West Gore, located in central Nova Scotia, was the only antimony mine in Nova Scotia, and contained significant concentrations of gold and silver. It was mined from 1883 to 1917, with the ore occurring as lenses of auriferous stibnite in fissure veins that occupy northwest and southeast faults. A minor anticlinal fold, on the east limb of the West Gore anticline, has some controlling aspect of the ore deposition and plunge of the ore shoot. Detailed information on the property can be found in the 2022 Battery Elements Corporation’s NI 43-101 Technical Report.
Cobalt
There are numerous anomalous cobalt mineral occurrences, geochemical anomalies, and alteration zones associated with the Cobequid-Chedabucto Fault Zone (CCFZ; Figure 1), a 300-kilometre-long crustal fault system within the Cobequid Highlands of northern mainland Nova Scotia, which is recognized as part of an Iron Oxide-Copper-Gold mineralized system. Examples of occurrences with highly anomalous cobalt concentrations include Sunny Brae, Specular Iron Mines, Mount Thom, and Bass River. There are also numerous cobalt occurrences worth investigating outside of the CCFZ, such as sites in Oceanview, Coxheath, and Nictaux Falls.
Manganese
In Nova Scotia, most of the known manganese occurrences/deposits are associated with replacement or vein-type processes of hypogene origin. The main historic manganese deposits are in western Nova Scotia at New Ross and Nicholsville, characterized by infilling of fault zones in granite and gabbro, respectively.
The largest manganese deposit in Nova Scotia occurs at New Ross, associated with the South Mountain Batholith, the largest composite batholith exposed in the Appalachians. The deposit was discovered in 1891, and was mined at two sites, the Cain and Riddle Mine, and the Dean and Chapter Mine. Approximate production for both mines totalled 3,000 tons of 50 to 60 per cent Mn over the mine life (intermittent between 1890s to the mid-1930s).
The New Ross and Nicholsville manganese prospects are augmented by the widespread (1700-kilometre contact) Goldenville-Halifax transition zone. This set of reactive strata between the carbon-rich Halifax Group and the siliceous Goldenville Group has never hosted a manganese mine but is likely the best source rock for future exploration. The Goldenville-Halifax transition zone is well documented through geophysical surveys and represents a widespread and continuous stratigraphic body. The transition zone is commonly thin, but often occurs in thick folded sequences and bifurcated, intercalated strata that are more amenable to exploitation.
Rare Earth Elements
Rare earth element (REE) mineralization mainly occurs in the Debert Lake area, in northern mainland Nova Scotia. The occurrence is hosted in a three-kilometre-long contact zone, where felsic volcanics and volcaniclastic rocks were intruded by high-level felsic plutonic rocks (approximately 350 Ma). Most of the REEs discovered occur in felsic to mafic volcanic rocks of the Byers Brook Formation, near the contact with the underlying granite. The REE-bearing minerals include fergusonite, chevkinite, allanite, monazite, and yttrialite. A metasomatic-hydrothermal vein model is proposed for the mineralization. From the samples analyzed to date, heavy REEs tend to dominate relative to light REEs, which is significant, as heavy REEs are of greater economic value.
Tungsten
Many of Nova Scotia’s saddle-reef gold deposits in the Cambro-Ordovician Meguma Supergroup contain appreciable amounts of scheelite. Two historic properties were mined with tungsten being the primary commodity, and gold secondary. The Stillwater Mine, to the west of the recently mined Touqouy Mine (Au; St Barbara Limited), was the province’s largest tungsten mine (mined from 1911 to 1919). The Indian Path Mine, in southwest Nova Scotia, was the second-most productive mine (mined sporadically from 1868 to 1900 for gold; 1926 to 1943 for tungsten). Cowan Mill Pond, Kempt Snare Lake, and Long Lake are other occurrences in Nova Scotia with strong tungsten potential. Many of these occurrences are hosted in greisen, bordering the contact zones of the Meguma Terrane with the South Mountain Batholith, or Musquodoboit Batholith.
Nova Scotia’s potential
There are other Nova Scotia critical minerals not discussed in this article, and discussed in Developing Canada’s critical mineral supply chain in Nova Scotia. Brazil Lake and Lower Caledonia have tantalum-niobium-bearing pegmatites, while the South Mountain Batholith has associated mineralized areas of indium and molybdenum (e.g., East Kemptville and New Ross). Gallium and germanium are associated with numerous zinc deposits in the province.
With Nova Scotia’s abundant natural resources, strong environmental principles, skilled labour, strategic location, strong business and academic communities, and favourable geology and location, the province is well-positioned to be a key player in the critical mineral sector, which will also create exciting opportunities for Nova Scotians.
